Hydraulic transmission



Jan. 9, 1940. w FERRE 2,186,409

HYDRAULIC TRANSMISSION Filed June 7, 1937 4 Sheets-Sheet lk INVENTD'R WALTER FERFHS ATTURNEY.

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Jan. 9, 1940. w` FERRIS 2,186,409

HYDRAULIC TRANSMISS ION Filed June '7, 1957 4 sheets-sheet 3' 3o soa e i INVENTUR o f5 0K/ALTER FERR@ .ATTURNEY- Jan. 9, 1940. w. F'ERR,V 2,186,409

HYDRAULIC TRANSMISSION Filed June 7. 1957 4 sheets-sheet 4 Patented Jan. 9, 1940 PATENT OFFICE HYDRAULIC TRANSMISSION Walter Ferris, Milwaukee, Wis., assignor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application June 7, 1937, Serial No. 146,784

6 Claims.

This invention relates to hydraulic transmissions of the type having both the pump and the motor thereof arranged inside a single casing. A transmission of this type has heretofore either had the pump cylinders connected directly to the motor cylinders or had the discharge port of the pump connected directly tothe inlet port of the motor and the exhaust port of the motor connected directly to the intake port of the pump.

The present invention hasasan object to provide a hydraulic transmission in which the hydraulic circuit thereof is externalized so that the motor may be controlled otherwise than by regulating the pump and so that liquid discharged by the pump may be utilized for driving an external motor or for other purposes.

A hydraulic transmission constructed according to the invention is illustrated in part schematically and in part in detail in the accompanying drawings in which the views are as follows:

Fig. 1 is an elevation of a transmission in which the invention is embodied. v

Fig. 2 is la sectional plan view taken on the irregular line 2-2 of Fig. 1.

lFig. 3 is a transverse section taken on the line 3-3 of Fig. 2.

Fig. 4 is a transverse section taken on the line 4--4 of Fig. 2.

Fig. 5 is a circuit diagram showing an outside 3 motor connected in series with the inside motor and with ar control valve in a position to enable the, pump to'deliver liquid to the inside motor and through itto the outside motor.

Fig. 6 is a view of a part of the circuit shown in Fig. 5 but with the control valve in position to bypass the pump and apply a brake load upon the inside motor. l

Fig. 7 is a circuit diagram showing an outside motor connected in series with the inside motor and with a control valve lin position to enable the pump to direct liquid rst. to the outside motor and through it to the inside motor.

Fig. 8 is a view of a part of the circuit shown in Fig. 7 but with the control valve in position to bypass the pump and the outside motor and to apply a brake load upon the inside motor.

The transmission has a pump I and a motor 2 arranged in a casing 3 which has one end thereo'f closed by an end head 4 and the other end 50 thereof closed by an end head 5. Casing 3 is provided intermediate its ends with an integral partition or pintle block 6' which divides the interior of casing 3 into a pump compartment and a motor compartment in which pump I and motor 2 are arranged respectively.

loi so-ss) Pump I and motor 2 have been shown as being of the rolling piston type which, since it is fully illustrated and described in Patent No. 2,074,068, will be but briefly described herein.

Pump I has its pistons 'l fitted in cylinders ar- 5 ranged radially in rotatable cylinder barrel 8 which is journaled upon a stationary valve shaft or pintle 9 through which liquid flows to and from the cylinders. Pintle 9 is xed in pintle block 6, as shown in Fig. 2, and providednear its free 1J end with two diametrically opposed ports I and II, as shown in Figs. and 7, with which each cylinder communicates alternately as cylinder barrel 8 rotates.

Pistons I have the outer ends or heads thereof 151 in contact with a thrust ring I2 which extends around cylinder barrel 8 and is eccentric thereto when the pump is delivering liquid. Thrust ring I2 is xed in a cylindrical thrust member I3 Which is rotatably mounted and adapted to be rotated in unison with the cylinder barrel by frictional contact between the piston heads and the thrust ring.

The parts just described are substantially the same in both the pump and the motor. Consequently, the corresponding parts of motor 2 have been indicated by corresponding reference numerals with the exponent a added and no description thereof will be given.

In order that the displacement of pump I may o be varied, thrust member I3 is rotatably supported by two bearings I4 and I5 which are carried by a slide block I6, while motor 2 has its thrust member AI3a supported by bearings I4 and I5 which are carried, respectively, by pintle block 6 and by end head 5 so` that the displacement of motor 2 cannot be varied.

Slide block I6 is restrained from movement axially of pintle 9 by pintle block 6 and by a plate I'l attached to end head 4, and it is restrained from vertical movement by slide plates or bearings (not shown) carried by casing 3.

The displacement of pump I kmay be varied by shifting slide' block I6 transversely of the axis of pintle 9 either mechanically, hydraulically or electrically according to the usual practice. As shown, slide block I6 is adapted to be shifted by means of a screw I8 which is fastened thereto and has a sleeve I9 threaded thereon and restrained from axial movement by a cap at- 50 tached to casing`3. Sleeve I9 maybe rotated by means of a hand wheel 2l iixed thereon, and it may `be locked in position by a lock nut 22 threaded upon the outer end of screw I8.

The arrangement is such that by loosening lock u nut 22 and then turning hand wheel 2| in one direction or the other, sleeve i9 will be rotated and move screw I8 outward or inward and thereby shift slide block I6 transversely of the axis of the pintle 8 to change the displacement of pump I. Then, lock nut 22 may be turned against hand wheel 2I to prevent screw I8 from turning and Athereby lock slide block 6 in its adjusted position.

Pump I is adapted to be driven by a shaft 23 which is connected to cylinder barrel 8 by means of a flexible coupling 24 and which is journaled in a bearing carried by end head 4 and in a bearing arranged in the end of pintle 9.

Motor 2 is adapted to drive a shaft 25 which is connected to cylinder barrel ila by means of a flexible lcoupling 24' and which is journaled in a bearing carried by end head 5 and in a bearing arranged in the end of pintle Se. I

When shaft 23 is rotated in the direction of the arrow shown thereon, pistons 1 will draw liquid into their cylinders from port I I and discharge it into port I0. When liquid is supplied to port I, it will enter the cylinders communicating therewith and force the pistons 1 in those cylinders outward, thereby causing cylinder barrel 8a to rotate shaft 25 in the direction of the arrow shown thereon. Rotation of cylinder barrel 8 causes liquid to be expelled into port IIP- by the pistons 1a in the cylinders communicating therewith.

A transmission of this type constructed according to the usual practice would have the discharge port of the pump connected directly to the inlet port of the motor and the exhaust port of the motor connected directly to the intake port of the pump by channels formed in the pintle axially thereof.

According to this invention however, the channels connecting the pump and the motor are brought to the outside of the casing so that the liquid discharged by the pump may be utilized for purposes other than driving the motor and so that the motor may be controlled otherwise than by regulating the pump, for example, so that a brake load may be applied to the motor. To this end, ports I0 and II communicate, respectively, .with two channels 30 and 3l (Figs.

2 and 5) which are formed in pintle 9 axiallyv thereof, and ports II)a and IIa communicate, re-

spectively, with two channels 3l)EL and 3lEL which are formed in pintle 9e axially thereof.

Pintles 9 and 8a have been shown as being integral but, in practice, they are made separately and channels 30, 3I, 30a and 3|a are drilled from the large ends thereof into communication with the pintie ports. Then the ends of these channels are plugged as indicated at 32 in Fig. 2, then the large ends of the two pintles are welded together, and then the pintles are pressed into a bore 33 formed in pintle blockl 6.

Channels 30 and 3I communicate, respectively, with two channels 34 and 35 (Figs.'2 and 3) which extend through the side of pintle 8 and through pintle block 6 to the outside of casing 3. Channels 30a and 3I.communicate, respectively, with two channels 34a and 35a (Figs. 2 and 4) which extend through the side of pintle 9 and through pintle block 6, to the outside of casing 3. Channel 34 also communicates through a channel 36 (Fig. 3) with the inlet of a relief valve 31 the outlet of which is connected through a channel 38 to channel 35 so that, if the pressure created by pump I exceeds a predetermined maximum, relief valve 31 will open and permit liquid to escape from high pressure channel 34 into return channel 35.

Channels 34, 35, 34 and 35a are connected to a distributing block which is arranged upon the outside of casing 3 and provided with such channels and valves as may be required to enable the transmission to perform the functions desired.

For the purpose of illustration, the transmission has been shown in Figs. 1 to 6 as having a distributing block 4I fixed to the outside of casing 3 and provided with a U-shaped channel 42 which connects channel 34 to channel 343 and' with a valve chamber 43 having four annular grooves or ports 44, 45, 46 and 41 formed in the Wall thereof and controlled by a valve 46 which is ordinarily provided with means for operating it`from a remote point but which, in order to simplify the view, has been shown provided with a handle 49 for operating it manually. In order that valve 46 may be shifted easily, the extreme ends of valve chamber 43 are connected to each other or are drained as indicated by the drain channels 50 and 5I shown in Figs. 5 and 6.

As best shown in Figs. 5 and 6, port 44 is connected by a channel 55 to channel 42, port 45 communicates with an external channel 56 and is connected by a channel 51 to channel 35', port 46 is connected by a channel 58 to channel 35*3J and communicates with the inlet of a resistance valve 59 which is arranged in block 4I, and port 41 communicates with the outlet of resistance valve 59 and also communicates with an external channel 60 through which liquid discharged by motor 2 may be delivered to an outside motor 6I to drive the same, the liquid discharged by motor 6I being returned to pump I through channel 56, port-45 and channel 35.

The transmission shown is particularly adapted for driving two parts of a single machine or two separate machines which are to be driven in unison but not necessarily in synchronism with each other.

For example, motor 2 may be employed to drive a machine or the delivery rolls of a machine, such as a printing press, which delivers material in asubstantially constant strip, and motor 6I may be employed to drive a Winder roll upon which the strip is wound as it is delivered thereto by the delivery rolls of the machine.

Thev strip is delivered to the Winder roll at a substantially constant linear speed which is determined by the adjustment of pump I. Since the peripheral speed of a roll increases relative to its rotary speed as its diameter increases, it

follows that the rotary speed of the Winder roll must be gradually decreased as the strip is wound thereon and that the torque of motor 6I must gradually increase as the strip accumulates upon the Winder roll in order to maintain a uniform tension upon the strip. Also, motor 6I must have a high starting torque to overcome the static inertia and friction of the Winder roll mechanism.

The apparatus yshown schematically in Fig. 5 for varying the speed of motor 6I and for enabling it to have al high starting torque is fullyl illustrated and described in Patent No. 2,078,268. Since this apparatus forms no part ofthe present invention, it is deemed sufficient to state herein that motor 6I has its outlet lconnected by 7 Vus rin diameter, the torque exerted by motor 6| will increase with a resultant increase in the pressure in channel 66, thereby increasing the rate at which liquid is bypassed so that motor 6| is gradually decelerated and enabled to maintain a substantially constant tension upon the strip.

In order to make up for leakage losses and to maintain a low pressure at the intake of pump a gear pump 61 is provided according to the usual practice. Gear pump 61 is arranged in a pump chamber which is formed in end head 4 and closed at its inner side by plate |1, and one gear of gear pump 61 is keyed upon shaft 23 as shown in Fig. 2. i

Gear pump 61 draws its supply of liquid from a reservoir (not shown) and discharges through a channel 68 and a check valve 69 (Figs. 3 and 5) into a channel 16 which communicates with channel 51. a relief valve 1| (Fig. 5) through which liquid discharged by gear pump 61 in excess of requirements is exhausted and which enables gear pump. 61 to maintain a low pressure in channel'51 and the channels communicating therewith.

When shaft 23 is rotated in the direction of the arrow and valve 48 is in the position shown in Figs. 2 and 5, liquid will now from pump through channels 36, 34, 42, 34a and 36a to the motor cylinders communicating with port I6a and cause motor 2 to rotate shaft 25 in the direction of the arrow. The liquid discharged by motor 2 will flow through port Ila, channels 3|, 35n and 58, port 46, valve chamber 4.3, port 41 and channel 66 to motor 6| and drive it. The

liquid discharged by motor 6| through channel 62 and valve 63 and the liquid bypassed through choke 64, resistance valve 65, channel 66 and valve 63 will iiow through channel 56, port 45 and channels 51, 35 and 3| to intake port When valve 48 is shifted to the position shown in Fig. 6, port 45 is opened to port 44 and port 41 is closed to port 46. The liquid'discharged by pump I will then iiow through channels 36, 34, 42 and 55, port 44, valve chamber 43, port 45 and channels 51, 35 and 3| to intake port Pump is thus bypassed and will deliver no liquid to the motors to drive them.

If the energy stored in the moving parts of the machine driven by motor 2 is sufficient to drive motor 2 and cause it to function as a pump, motor 2 will draw liquid into its cylinders through channels 365, 34a, 42 and 55, port 44, valve chamber 43 and port 45 from channel 51 which is supplied with liquid from gear pump 61 and bythe liquid discharged by motor 6|. The liquid-discharged by motor 2wil1 flow through channels 3|, 35a and 58, port 46, resistance valve 59, port 41 and channel 66 to motor 6| to keep motor 6| running las long as motor 2 continues to run. Resistance valve 59 will resist the discharge of liquid therethrough and thereby exert a brake load upon motor 2 to quickly decelerate it to a complete stop. The liquid discharged by motor 6|; will Channel 16 also communicates with flow through the above described channels to the intake of pump If it is desired that motor 2 be at times operated independently of an outside motor which at other times is energized by pump I, the transmission may be provided with a distributing block having a diierent arrangement of valves such, for example, as the valve arrangement shown in Figs.

'1 and 8 in which a distributing block 15 is shown provided with a control valve 16 and a bypass valve 11 having handles 18 .and 19 attached thereto for operating them manually but, in practice, such valves are ordinarily provided with means operating them from a remotepoint.

Valve 16 is tted in a valve' chamber 86 which has three annular grooves or ports 8|, 82 and 83 formed in the wall thereof, and valve 11 is tted in a valve chamber 84 which has two annular grooves or ports 85 and 86 formed in the wall thereof. The ends of \valve chambers 86 and 84 are suitably drained in order to permit the valves to be shifted easily. As shown, the left end of both chambers 86 and 84 are connected to a drain channel 81l and valves 16 and 11 are provided, respectively, with channels 88 and 89 which extend longitudinally therethrough.

When valve block 15 is attached to casing 3, channel 34 communicates through a channel 96 with port 8|, channel 35 communicates through a channel 9| with port 82, channel 35a communicates through a channel 92 with port 83 and channel 34a communicates through a channel 93 with port 86. In order to simplify the view, channel 93 has beenshown as an external channel but, in practice, it is arranged inside of block 15. Port 85 is connected by -a channel 94 to port ,8| and by a channel 95 to the inlet of a motor with channel 16 which communicates with gear pump relief valve 1|, and gear pump supply channel 68 communicates through check valve 69 with channel 16 as previously explained. Channel 92 communicates with the inlet of a resistance valve 98 the outlet of which is connected by a channel 99 to channel 9|.

The arrangement is such that, when pump is being driven and valves 16 and 11 are in the positions Shown in Fig. 7, the liquid discharged by pump will ow through channels 36, 34 and V96, port 8|, channel 94, port 85 and channel 95 to `motor 96 and drive it. The liquid discharged by motor 96 will flow through channels 91, 93,

34a and 36 to motor 2 and drive it. The liquid discharged by motor 2 will flow through channels 3|a, 35a and 92, port 83, valve chamber 86, port 82 and channels 9|, 35 and 3| to the intake of pump The liquid supplied by pump thus drives both of the motors.

If valve 11 isA shifted to the position shown in Fig. 8 and valve 16 remains in the position shown in Fig. 7, the liquid delivered by pump through the above described channels to port 85 will iiow therefrom through valve chamber 84, port 86 and channels 93, 34a and 36a to motor 2 and drive it but motor 96 will remain idle for the reason that it was short circuited by shifting valve 11 to open port 85 to port 66.

If valve 16 is shifted tothe position shown inl 'lov Y stored in the moving parts of the machine driven by motor 2 is sufiicient to drive motor 2 and cause it to function as a pump, motor 2 will draw liquid into its cylinders from the pump circuit and discharge liquid through channels 3l, 35a and 92, resistance valve 9B and channel 99 into the pump circuit. Resistance valve 98 will resist the discharge of liquid therethrough and thereby function to apply a brake load upon motor 2 only if valve 11 is in the position shown in Fig. 8 and to apply a brake load upon both motors if valve 11 is in the position shown in Fig. '7.

From the foregoing description of two illustrative circuits it will be obvious that, by simply changing the channels and valves in the distributing block, many other circuits may be produced without departing from the scope of the invention as hereafter claimed.

The invention is hereby claimed as follows:

1. A hydraulic transmission, comprising a closed casing, a pump arranged within one part of said casing and provided with an intake port and a discharge port, a motor arranged within another part of said casing and provided with an inlet port and an exhaust port, a distributing block arranged upon the outside of said casing, a uid channel connecting each of said ports to said block, a motor arranged outside said casing, fluid channels connecting said outside motor to said block, and valve means arranged within said block for short circuiting said pump or directing liquid from said pump to one or both or said motors.

2. A hydraulic transmission, comprising a closed casing, a pump arranged within one part of said casing and provided with an intake port and a discharge port, a motor arranged within another part of said casing and provided with an inlet port and an exhaust port, a distributing block arranged upon the outside of said casing, a iluid channel connecting each of said ports to said block, a relief valve arranged outside said casing, a motor arranged outside said casing, fluid channels connecting said outside motor to said block, and valve means arranged within said block and operable either to direct liquid from said pump to said motors or to bypass saidpump and simultaneously direct the discharge from at least one of said motors through said relief valve.

3. A hydraulic transmission, comprising a closed casing, a pump arranged within one part of said casing. and provided with an intake port and a discharge port, a motor arranged within another part of said casing and provided with an inlet port and an exhaust port, a distributing block arranged upon the outside of said casing, a fluid channel connecting each of said ports to said block, a second motor arranged outside said casing, fluid channels connecting said outside motor in series with said inside motor, a resistance valve,and valve means arranged within said block for controlling communication between certain of said channels and operable to cause liquid to flow from said pump to said moor to short circuit said pump tors in sequence and one of said motors and cause the liquid discharged by the other motor to be directed through said resistance valve.

'4. A hydraulic transmission, comprising a closed casing, a distributing block arranged upon the outside of said casing, a pintle block formed upon the inside of said casing integral therewith and provided with a central bore and with a plurality of iiuid channels connecting said bore to said distributing block, a pump arranged within said casing at one side of said pintle block and having a central valve shaft or pintle fixed in said bore and provided with intake and discharge passages which communicate with certain of said channels, a motor arranged within said casing at the other side `of said pintle block and having a central valve shaft or pintle fixed in said bore and provided with inlet and exhaust passages which communicate with other of said channels, a motor arranged outside said casing, fluid channels connecting said outside motor to said distributing block, and valve means arranged within said distributing block for controlling communication between certain of said channels and operable to either short circuit said pump or to direct liquid therefrom to one or both of said motors.

5. A hydraulic transmission, comprising a closed casing, a distributing blockarranged upon the outside of said casing, a pintle block formed upon the inside of said casing integral therewith and provided with a central bore and with a plurality of fluid channels connecting said bore to said distributing block, a pump arranged within said casing at one side of said pintle block and having a central valve shaft or pintle fixed in said bore and provided with intake and discharge passages which communicate with certain of said channels, a motor arranged Within said ycasing at the other side of said pintle block and having a central valve shaft or pintle fixed in said bore and provided with inlet and exhaust passages which communicate with other of said channels, a motor arranged outside said casing, fluid channels connecting said outside motor to said distributing block in series with said inside motor, a resistance valve, and Valve means arranged within said distributing block for controlling said motors and operable to direct the discharge from at least one of said motors through said resistance valve.

6. A hydraulic transmission, comprising a closed casing, a distributing block arranged upon the outside of said casing, a pintle block formed upon the inside of said casing integral therewith and provided with a plurality of fluid channels communicating with said distributing block, a pump arranged within said casing at `one side of said pintle block and having a central valve shaft or pintle supported by said pintle ,block and provided with intake and discharge passages which communicate with certain of said channels, a motor arranged within said casing at the other side .of said Vpintle block and having a central valve shaft or pintle supported by said pintle block and provided with inlet and exhaust passages which communicate with other of said channels, a second motor arranged outside said casing, and valve means arranged in said distributing block to control communication between certain of said channels and operable to either bypass said pump or to direct liquid therefrom to one or to both of said motors.

WALTER FERRIS. 

